Gamma-ray Burst 050713B

(All information courtesy of the instrument teams.)

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 13 Jul 05 12:11:28 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     145754,   Seg_Num: 0
GRB_RA:          307.843d {+20h 31m 22s} (J2000),
                 307.870d {+20h 31m 29s} (current),
                 307.597d {+20h 30m 23s} (1950)
GRB_DEC:         +60.920d {+60d 55' 12"} (J2000),
                 +60.939d {+60d 56' 20"} (current),
                 +60.750d {+60d 44' 59"} (1950)
GRB_DATE:        13564 TJD;   194 DOY;   05/07/13
GRB_TIME:        43637.62 SOD {12:07:17.62} UT
TRIGGER_INDEX:   491
GRB_PHI:         128.96 [deg]
GRB_THETA:        45.40 [deg]
DELTA_TIME:      65491.00 [sec]
LC_URL:          sw00145754000msb.lc
SUN_POSTN:       112.91d {+07h 31m 39s}  +21.77d {+21d 46' 05"}
SUN_DIST:         96.41 [deg]
MOON_POSTN:      187.70d {+12h 30m 49s}   -2.48d {-02d 28' 32"}
MOON_DIST:       106.36 [deg]
MOON_ILLUM:      39 [%]
GAL_COORDS:       96.11, 12.46 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      359.13, 72.65 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.

red DSS finding chart ps-file (from revised position - GCN 3600)

GCN/SWIFT NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 13 Jul 05 12:11:28 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     145754,   Seg_Num: 0
GRB_RA:          307.843d {+20h 31m 22s} (J2000),
                 307.870d {+20h 31m 29s} (current),
                 307.597d {+20h 30m 23s} (1950)
GRB_DEC:         +60.920d {+60d 55' 12"} (J2000),
                 +60.939d {+60d 56' 20"} (current),
                 +60.750d {+60d 44' 59"} (1950)
GRB_DATE:        13564 TJD;   194 DOY;   05/07/13
GRB_TIME:        43637.62 SOD {12:07:17.62} UT
TRIGGER_INDEX:   491
GRB_PHI:         128.96 [deg]
GRB_THETA:        45.40 [deg]
DELTA_TIME:      65491.00 [sec]
LC_URL:          sw00145754000msb.lc
SUN_POSTN:       112.91d {+07h 31m 39s}  +21.77d {+21d 46' 05"}
SUN_DIST:         96.41 [deg]
MOON_POSTN:      187.70d {+12h 30m 49s}   -2.48d {-02d 28' 32"}
MOON_DIST:       106.36 [deg]
MOON_ILLUM:      39 [%]
GAL_COORDS:       96.11, 12.46 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      359.13, 72.65 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-BAT GRB Lightcurve.
COMMENTS:
COMMENTS:        The next comments were copied from the BAT_POS Notice:
COMMENTS:        This is a rate trigger.
COMMENTS:        A point_source was found.
COMMENTS:        This does not match any source in the on-board catalog.
COMMENTS:        This does not match any source in the ground catalog.
COMMENTS:        This is a GRB.

GCN notice #3590
S. Vaughan (Leicester), A. Falcone (PSU), D. Palmer (LANL), A. Blustin (MSSL), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), H. Krimm (GSFC/USRA), D. Burrows, D. Morris, C. Gronwall (PSU), C. Markwardt (GSFC/UMD), K. Page, M. Goad (Leicester), S Rosen (MSSL), N. Gehrels (GSFC)
At 12:07:17.62 UT, the Swift Burst Alert Telescope (BAT) triggered and located on-board GRB050713B (trigger=145754). The spacecraft slewed immediately. The flight-determined location is RA,Dec 307.843,+60.920 {20h 31m 22s,+60d 55' 12"} (J2000) with an uncertainty of 3 arcmin (radius, 90% c.l. stat+sys). The burst lightcurve has 1 (maybe 2) peaks within ~30 sec duration. It is riding on top of two long bumps which are believed to be background, but without the full Malindi data, we can not determine if the bumps are background or burst-related. The peak rate (without bumps) is ~1000 cnts/sec in the 15-350 keV band.
The spacecraft slewed immediately and the XRT began observing the burst at 12:09:33 UT (136 s after the BAT trigger). XRT found a bright, uncataloged, fading X-ray source at:
```
RA:  +20h 31m 15.5s (J2000),
DEC: +60d 56' 38.4" (J2000).
```
This position is 100 arcseconds from the BAT position. The estimated uncertainty is 6 arcseconds radius (90% containment).
The Swift Ultra Violet/Optical Telescope (UVOT) observations began at 12:09:33 UT, 136 seconds after the BAT trigger. The first data taken after the spacecraft settled was a 100 sec exposure using the V filter with the midpoint of the observation at 186 sec after the BAT trigger. Based on comparisons to the DSS, we detect no new source at the XRT position.
GCN notice #3592
C. Guidorzi, R.J. Smith, C.G. Mundell, A. Monfardini, A. Gomboc, I. A. Steele, C.J. Mottram, D. Carter, M.F. Bode (Liverpool JMU), P. O'Brien, N. Bannister, E. Rol (Leicester), on behalf of the RoboNet-1.0 collaboration report:
"The 2-m Faulkes North Telescope followed up robotically the GRB050713B detected by SWIFT (Vaughan et al., GCN 3590) 3.3 min after the GRB trigger time. The automatic "detection mode" procedure didn't detect any obvious candidate to about R=18.2 from 3 10-s images (mean epoch of 3.8 min after the GRB), with FOV of 4.6'x4.6' centred on the BAT in-flight location. The above limit is also confirmed by visual inspection of the images.
The limiting magnitude is automatically calculated with respect to the USNOB1.0 'R2' values of the field objects.
Further observations are ongoing.
This message can be cited"
GCN notice #3593
Z.Y. lin(NCU), K.Y. Huang, W.H. Ip (NCU), Y. Urata(RIKEN), Y. Qiu (BAO), Y.Q. Lou (THCA) on behalf of EAFON report:
" We have performed R-band imaging for the entire error region of GRB 050713b (Vaughan et al. GCN 3590) from 24 min after the burst with Lulin 1-m telescope. No source was detected at position of the fading X-ray source during our observation with following limiting magnitude derived from the USNO-B1.0 catalogue.
```
UT      Exposure    Filter     Limiting
Start   Time                      Magnitude
12:31   300 s       R          21.2
12:37   300 s       R          21.6
12:43   300 s       R          21.3
12:49   300 s       R          21.6
12:54   300 s       R          21.6
```
This message may be cited."
GCN notice #3600
A. Parsons (GSFC), S. Barthelmy, L. Barbier (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (NASA GSFC/UMD), F. Marshall (GSFC), D. Palmer (LANL), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), A. Smale (NASA HQ), M. Suzuki (Saitama), J. Tueller (GSFC) on behalf of the Swift-BAT team:
Using the full data set from the recent telemetry downlink, further analysis of Swift-BAT GRB 050713B (Trigger #145754; Vaughn et al., GCN Circ 3590) yields a refined position of RA, Dec 307.820, +60.938 {20h 31m 17s, +60d 56' 17"} (J2000) with an uncertainty of 3 arcmin (radius, 90% confidence, statistical+systematic). The light curve shows a FRED-like profile of total duration ~75 seconds.
The spectrum over the interval from T-2 to T+178 seconds can be fit with a power law with photon index 1.56 +/- 0.13 and yields a fluence of 8.2 +/- 1.0 X 10^-6 erg/cm^2 in the 15-350 keV band. The peak flux in a 1-sec wide window starting at T+4.4 seconds is 2.2 +/- 0.6 ph/cm^2/sec.
GCN notice #3602
K. Page, S. Vaughan, M. Goad (Leicester), D. N. Burrows (PSU), M. Ajello (MPE), R. Fink and N. Gehrels (GSFC) report on behalf of the Swift XRT team:
We have analysed the first two orbits of data for GRB050713b (GCN 3590, Vaughan et al., 2005). Using xrtcentoid, the refined position is:
```
RA(J2000) = 20h 31m 15.5s
Dec(J2000) = +60d 56' 40.4"
```
with an uncertainty of 6 arcsec. This is only 2 arcsec from the original XRT position (GCN 3590, Vaughan et al., 2005).
The light-curve shows a steeply fading afterglow during the first orbit, with a decay slope of alpha = 2.88 +/- 0.12 between 143 and 600 seconds after the trigger. After ~5000 seconds (i.e. on the second orbit), the light-curve flattens significantly; more data are required to constrain the slope following the break in the light curve.
The WT spectrum can be fitted by an absorbed power-law with a spectral index, Gamma = 1.70 +0.11/-0.09 and excess NH of (1.97 +0.50/-0.43)e21 cm^-2.
The unabsorbed 0.3-10 keV flux (averaged over 143 and 330 seconds after the burst) is (9.02 +0.16/0.80)e-10 erg cm^-2 s^-1.
GCN notice #3603
S. Rosen (MSSL), S. Vaughan (Leicester), R. Fink (GSFC-SPSYS), M. Chester (PSU) report on behalf of the Swift UVOT team:
Using summed images from Swift/UVOT of the field of GRB 050713B, taken from 136 seconds after the BAT trigger, no new source is detected within the XRT error circle (Vaughan et al., GCN 3590) in any of the six filters down to the following 3-sigma magnitude upper limits:
```
Filter   Exposure (s)  T_mid (s)   3-sig limit
V        252           598         19.26
B         88           624         19.58
U         88           610         19.31
UVW1      88           596         19.46
UVM2      88           582         19.83
UVW2      88           639         19.87
```
where T_mid is the mid-point of the summed observation.
We caution that the instrument is not yet fully calibrated and that the magnitude limits presented here may need to be refined.
GCN notice #3617
I. Bikmaev, A. Galeev, N. Sakhibullin (KSU/AST), I. Khamitov, Z. Aslan (TUG), U. Kiziloglu (METU), A. Alpar (SabUni), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), report:
We have observed the field of GRB050713b (Vaughan et al. GCN 3590) on July 14, 2005, in Rc-band with ANDOR CCD attached to the 1.5-m Russian-Turkish telescope (RTT150, Antalya, Turkey). The set of 30 sec exposures has been made with total exposure time of 15 min and midpoint at UT = 22h 26min (~ 22 hours after the burst). No new optical source was detected at the position of the X-ray source in the co-added frame with limiting magnitude of Rc = 22.4 mag.
This message may be cited.
GCN notice #3701
D. Sharapov, M. Ibrahimov (MAO), V.Rumyantsev (CrAO), A.Pozanenko (IKI) on behalf of larger GRB follow up collaboration report:
We observed the error box of GRB050713b (Trigger #145754; Vaughn et al., GCN 3590, Parsons et al., GCN 3600) with 1.5m telescope (Maidanak Astronomical Observatory) on July 13, 14, and 15. Limiting magnitude of stacked image of observation obtained on July 13 (start time July 13 UT 18:06, i.e. ~6.0 h after burst) is R=23.2. We detected optical sources S1 which is offset ~1.9 arcsec of the refined XRT error circle (Page et al., GCN3602) and have the following coordinates (uncertainty in each coordinate is about 1 arcsec):
S1 RA(J2000)= 20 31 15.96 Dec(J2000) = +60 56 36.4
Photometry of the source based on USNO A2.0 catalog is following:
```
Mean time         Exposure   S1
  (UT)               sec.    mag.

July 13, 18:56    15x300     24.13 +/-0.74
July 14, 19:44     8x300     22.90 +/-0.44
July 15, 19:31     9x300     22.93 +/-0.30
```
Since the S1 source does not demonstrate fading behavior, it is unlikely that S1 is an OT of GRB050713b.
Stacked image of July 13 observations can be found in http://grb.rssi.ru/GRB050713b
This message may be cited.

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Jochen Greiner, last update: 30-Jul-2005 [Disclaimer]